Question 1138413
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Here is a solution using an alternative to the usual algebraic methods.  If you understand this method, it will get you to the answer to mixture problems like this much faster and with far less work than any of the algebraic methods.<br>
(1) The target percentage (7) is 1/3 of the way from the lower percentage (5) to the higher percentage (11).<br>
(It might help you see what I'm saying there by plotting the 5, 7, and 11 on a number line; 7 is 1/3 of the way from 5 to 11.)<br>
(2) That means 1/3 of the mixture has to be the higher percentage.<br>
ANSWER: 1/3 of 600ml, or 200ml of 11%; so 400ml of 5%.